Knox watched both men as Williams walked over to the sofa Laing had already eased himself into with his left leg stretched out in front of him, and White hung back near the door. Neither of them looked thrilled or devastated with how their afternoons had gone, and Knox wished they were at least one of the two. After he and Bennett had seen nothing unusual while they’d been tailing Kosygin, he hoped White might have released something else locked away in Williams’s mind that would confirm there was still a would-be killer out there and maybe, if they were very lucky, their identity.

‘Laing discharged himself from Guy’s and insisted on coming back to work,’ Holland said.

‘I won’t be a lot of help,’ Laing said, stroking the thick padding wrapped round his thigh. ‘But I thought another head might be useful.’

Knox hadn’t been surprised when Laing had appeared at Leconfield House on crutches twenty minutes earlier. Now the young officer was involved, Knox was sure he’d do whatever he could to stay that way.

‘I’ve filled him in on what we think we know,’ Holland said. ‘Anything you want to add, Malcolm?’

‘Only that I haven’t changed my opinion,’ White replied. ‘I’m still inclined to believe Williams. Or at least believe that he believes something very serious is going on.’

Knox was buoyed by White’s confidence in his best friend, but then realised that meant he would have to play devil’s advocate.

‘There was no sign of any plot in motion against Kosygin at the TUC or in Whitehall,’ he said.

‘But they weren’t easy targets,’ Laing replied. ‘We’ve done what we can with the ballet, but the Royal Opera House is a public building. There’ll be almost two thousand people in the audience tonight and we can’t question them all as they walk through the doors.’

Knox was glad he’d chosen not to bring up that he’d warned Knox two days ago about the risk of this exact eventuality.

‘We definitely can’t cancel the performance?’ Knox asked.

‘I doubt the BBC would forgive us,’ Holland replied. ‘Or my wife.’

‘I don’t see why Kosygin’s so determined to see Nureyev perform,’ Laing said. ‘I thought he was still a major embarrassment.’

‘It’s not about the dancing,’ Bennett. ‘It’s about sending a message.’

‘Asking him to come home?’

‘Or telling him and everyone else who’s made it through the Iron Curtain that they never really escaped. That wherever they go, Russia can still get to them.’

Everyone let that possibility sink in for a few moments, before Holland spoke again.